And our line of Erl-Kings ends and a new lineage of human elementals begins. Splendid. What took you so long? 
Swamp Thing (Volume 2) #80 is an issue of the series Swamp Thing (Volume 2) with a cover date of December, 1988.
Synopsis for "The Longest Day"
Somewhere in space, the earth elemental known as Bog Venus is exploring a planet covered in bio-circuitry made up of plant life. While she cannot comprehend the function of the planet's circuits, she senses that all of its energies are currently focused on Earth.
In the Louisiana swamps, the Swamp Thing uses his abilities to create furniture out of hardwood, in order to satisfy his wife Abby's nesting instinct. All of these efforts are in preparation for the coming of their child, who is to be the host for the next earth elemental. Abby is very content with the way things have been going, but suddenly realizes that every time she's content, Swamp Thing has to leave on some important adventure.
Sheepishly, he admits that he plans to go to see the Parliament of Trees, to explain that the crisis with the Sprout has been averted. Abby reluctantly lets him go, offering that she will go to Houma to purchase some new clothes to fit around her pregnancy, and to visit her friends Chester Williams and Liz Tremayne.
Elsewhere in space, the earth elemental known as Ghost Hiding in the Rushes meditates and observes a strange plant-based machine which seems to sing in a discordant melody that directs it's focus with pinpoint accuracy toward Earth.
The Swamp Thing goes to Brazil where he confers with the Parliament elder, Alex Olsen. Olsen reveals that, to some extent, the Parliament engineered the Swamp Thing's actions, and that despite appearances, they were only guiding him toward the ultimate outcome of having the first human host for a plant elemental, signalling the end of the Erl-Kings.
Olsen warns, however, of a menace from beyond the stars that will soon seek to destroy him. Alec quickly grows frustrated, believing it to be another trick. He exclaims that he will deal with whatever threat faces him. He will be the one who shapes the future of the next elemental, not the Parliament. Swamp Thing leaves before he can hear Olsen further warn that one of the oldest trees in the Parliament expects to see him soon.
In space, the earth elemental known as Saint Columba marvels at the light of an enormous crystal asteroid, taking in the light from a red sun. He notices that the refracted light is bouncing back toward Earth.
Swamp Thing returns to his home, regretting his words at the Parliament. He knows that a warning from the others should not be taken lightly. With Abby still gone, and a sense that he will not be home again for some time, Swamp Thing struggles to think of a way to show what's happening. He decides to create a wedding band of vegetable matter, and leave it behind for her as a symbol of their love.
Somewhere in Space, the earth elemental Kettle Hole Devil (New Earth) discovers a giant vegetable supercomputer whose information is all being loaded out into space toward the Earth. From afar, the Dominators watch on their viewing screen, confounded by the fact that all four of the Parliament's Committee are being drawn to earth - the Dominators' next target.
As it turns out, the four planets that the elementals were drawn to had had their vegetation weaponized by the Dominators as part of a Matrix Disruptor to be used in a preemptive attack against the Swamp Thing - the only person who could easily defeat their vegetation-based weaponry.
Swamp Thing travels to the North Pole, where he expands his consciousness across the entirety of the planet. He feels more powerful and confident than ever before, as he begins to sense the entirety of the planet at once. Suddenly, though, things take a turn for the worse. He begins feeling overwhelming negativity in subatomic particles falling from space, stress fractures within the earth, the weight of human existence and pollution. He realizes that this is the attack he was warned of.
Desperately, he tries to escape into his astral form, but the Dominators' Matrix Disruptor is still effective, and once they match his frequency, they have him trapped. With the Swamp Thing no longer a threat, only the four remaining elementals are of concern to the Dominators.
Back in Louisiana, Abby returns home with Chester Williams. Abby immediately senses that something is wrong, and when Chester follows, they are horified to find that her new home is now petrified and lifeless.
Appearing in "The Longest Day"
Featured Characters:
Supporting Characters:
Antagonists:
- Dominators (Behind the scenes)
Other Characters:
- Parliament of Trees
- Demons (Cameo)
Locations:
- Louisiana
- South America
- Hell (Cameo)
- New York City (Cameo)
- North Pole
Items:
Vehicles:
- Chester's boat
Notes
- Issue published with a Winter, 1988 cover date (December).
- This issue is a prologue to the 1988-89 "Invasion!" crossover event.
- Alex Olsen is the original Swamp Thing and was introduced in House of Secrets #92.
- The elder member of the Parliament that he is forwarding the message from is revealed in Swamp Thing Vol 2 89 to be Yggdrasil. While accurate, the message holds a subtler meaning than it appears to.
- Chester Williams makes reference to meeting Superman. This took place last issue.